Ok, so I am by no means pretending to be a top notch photographer like the majority of people on this forum, but I am looking for a little advice if someone is willing to give it. I have been taking photographs for many years just for fun and recently after many people inquiring into how much I would charge for their photographs I decided to pursue a business.

The business of photography has nothing to do with photography. You need a business plan. Insurance. Taxes. Etc.

I have taken a few classes trying to improve my skills but there is something that is simply bugging me. I have a Nikon D3200 and I try my best to get the Aperture and Shutter speed right for indoor photographs without flash, but I seem to be having a terrible time. They come out blurry or underexposed and I was just curious if maybe someone could offer a little bit of friendly insight into what I may be doing wrong. Thank you.

Sound as though you don't understand exposure. And exposure is fairly fundamental if you plan on charging for photography. I might suggest picking up Bryan Peterson's Understanding Exposure as a place to start. That said, your camera is a tool used to record light, to record an exposure. In low light, the shutter needs to stay open longer in order to capture enough light to make an exposure. The slower the shutter, the blurrier the image. Just because you want a fast shutter doesn't mean you can use a fast shutter. Another very important part of photography is understanding light. Low light and professional photography are good companions. Your first line of defense is learning how to light something, whether that be with flash or ambient light.